I think the bonuses from monster cards are a bit weak. What good does +1 jump do me? Might be worth looking into buffing some of the lacklustre ones so it's actually exciting to find the card. Just to be clear, I'm talking about individual card bonuses you get whenever you pick up a card and not the exp bonus when you complete a set. Some of them are nice, like increased resists or something, but ones that add like +1 speed? Totally worthless. ETA: I don't really have an ideas about how these could be buffed or changed. Just remarking that finding a card should be exciting beyond just grinding to complete a set. It would also make finding cards again exciting (after you complete the set).
That would effectively be an almost permanent 15% exp bonus for people's favorite grinding spot after the first card, I don't think it's something healthy for the game. But I am for reworking some cards so that they make getting them while grinding for the set, or for a quest, or mob grinding, it will feel like a meaningful benefit for a few minutes. An example for a memorable card for me was protolord. This mob has a stun spam, but the card gives you stun immunity for a while, so seeing that card drop massively improves your QoL while grinding there. Not all cards needs to be this extreme, but a buff that actually makes a difference once in a while will be appreciated.
A counter in the monster book after 5 would be nice. So it counts 6,7,8,9,… The additional stats is a bonus as well
Coming from someone who did a lot of card hunting. I don't see any need to buff the card effects. Getting a card most of the time is far from a big deal, the reward therefore shouldn't be too big either. Yes, +1 jump in such and such area is completely useless, but I don't see how that's a problem at all, cards are free anyways.
I think this is not about fixing a problem, but a suggestion to make something better or more useful. PS. The card at dreamy ghost gives no stat at all.